Synthesis, characterization and transport properties of the solid solution BaPb1-xSnxO3 (0 ≤ x ≤ 0.4 and x = 1).

The transport properties of the perovskites BaPb1 − xSnxO3 (0 ≤ x ≤ 0.4, and x = 1), synthesized for the first time, are investigated in the range (300 –4.2 K). They were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and FTIR-ATR spectroscopy. The weak thermal dependence of conductivity on temperature is characteristic of degenerate behavior with a finite density of states at the Fermi level. The linear behavior indicates a thermally activated mobility (= 4.8 × 10− 6 cm2 V− 1 s− 1) while the negative sign of the thermo-power, indicates that the mobile carriers are electrons, due to non-stoichiometry of oxygen. The band overlapping O2−: 2p-Pb: 6s is involved in the semi-metal BaPbO3. The magnetic susceptibility exhibits a Pauli-type paramagnetism due to itinerant electrons. A pronounced dip, associated with a phonon drag contribution is observed near 25 K. The non-linear dependence of log σ vs. T− 1 at low temperatures results from a variable range hopping evidenced by the plot log σ vs. T− 0.25. The metal-non-metal transition is of Anderson type due to random potential introduced by substituting Pb4+ with Sn4+. The capacitance− 2 potential (C− 2 - E) plots show linear behaviors from which flat band potentials are determined (-0.22 - -0.83 VSCE). The Electrochemical Impedance Spectroscopy exhibits semicircles assigned to the capacitive behavior with a low density of surface states within the gap region. [ABSTRACT FROM AUTHOR]